Unit 6 Particles with Internal Structure 3-1

Transcription

1 Unit 6 Particles with Internal Structure 3-1

2 The Elements Remember, elements are combined to form molecules the way letters are combined to form words. Presently there are about 115 known elements. Only 88 occur naturally, the rest are made in laboratories. Only 9 elements account for most of the compounds found in the Earth s crust. 3-2

3 Table

4 All living things are made up, mainly, of oxygen, carbon, hydrogen and nitrogen. 3-4

5 Symbols For The Elements Just as each state has a two-letter abbreviation, each element has a one- or two-letter symbol to make life simple for chemists. Some elements found in the human body are: As, Cr, Co, Cu, F, I, Mn, Mo, Ni, Se, Si, & V. Notice the first letter is ALWAYS capitalized and the second letter, if present, is Not capitalized. 3-5

6 Symbols For The Elements Some symbols make sense like O for oxygen and H for hydrogen or Ni for nickel. Others, like Pb for lead or Fe for iron, don t automatically make sense; they originated from the Greek or Latin names of plumbum (Pb) and ferrum (Fe). 3-6

7 Dalton s Atomic Theory Scientists studying matter in the eighteenth century made the following observations: Most natural materials are mixtures of pure substances. Pure substances are either elements or combinations of elements called compounds. A given compound always contains the same proportions (by mass) of the elements. John Dalton attempted to explain these observations in

8 Dalton s Atomic Theory 1. Elements are made of tiny particles called atoms. 2. All atoms of a given element are identical. 3. The atoms of a given element are different from those of any other element. 4. Atoms of one element can combine with atoms of other elements to form compounds. A given compound always has the same relative numbers and types of atoms. 5. Atoms are indivisible in chemical processes. That is, atoms are not created or destroyed in chemical reactions. A chemical reaction simply changes the way atoms are grouped together. 3-8

9 Formulas of Compounds The types of atoms and the number of each type in each unit (molecule) of a given compound are conveniently expressed by a chemical formula. The atoms are indicated by their symbols and the number of each type is indicated by a subscript (unless there is only one). Ex) C 6 H 12 O 6 or H 3 PO 4 3-9

10 Practice Write the formula for each of the following compounds, listing the elements in the order given: a. A molecule contains four phosphorous atoms and ten oxygen atoms. b. A molecule contains one uranium atom and six fluorine atoms. c. A molecule contains one aluminum atom and three chlorine atoms. 3-10

11 What is inside an atom? 3-11

12 Modern Atomic Structure Every atom is composed of the three basic subatomic particles. (Protons, electrons, neutrons) Different elements have different numbers of each of these subatomic particles. The reason one element behaves differently than another lies in the number and arrangement of their electrons. When atoms get close to each other their electron clouds can overlap and interact. 3-12

13 Figure 3.9: A nuclear atom viewed in cross section. 3-13

14 In any box on the Periodic Table, what information can you find? 6 C Average Atomic Mass = Protons + Neutrons the weighted average of all the mass numbers for each isotope of the element Atomic number = number of protons, unique for every element, no 2 elements have the same atomic # Element symbol = can be 1,2 or 3 letters, first letter is always capitalized, and succeeding letters are always lower case 3-14

15 Isotopes Two atoms of the same element (same number of protons) with different numbers of neutrons. 3-15

16 Figure 3.10: Two isotopes of sodium. 3-16

17 Isotopes There are two important numbers associated with any given element: 1. Atomic Number The number of protons in a nucleus. 2. Mass Number The SUM of the number of protons AND neutrons (a.k.a. nucleons) in a nucleus (NOT the sum of their masses). We should note that two different isotopes will have the same atomic number, but different mass numbers. 3-17

18 Isotopes The two previous examples of isotopes of sodium would be: 23 Na Na 11 The example on the left would contain 11 protons and 12 neutrons (23-11=12). The example on the right would contain 11 protons and 13 neutrons (24-11=13). 3-18

19 Practice Problems Write the symbol for each of the following atoms, and list the number of protons, neutrons, and electrons for each. 1) The cesium atom with a mass number of ) The iron atom with a mass number of 56. 3) The krypton atom that has 48 neutrons. 4) The nitrogen atom that has 6 neutrons. 3-19

20 Weighted Average Atomic Mass Remember elements can have different isotopes which means that they vary in their number of neutrons. If you have 3 different isotopes of the same element: 15 atoms have a mass of 21 8 atoms have a mass of 23 2 atoms have a mass of 19 We can calculate the weighted average by multiplying the number of atoms by their mass: (15) (21) = = (8) (23) = (2) (19) =+ 38 average atomic mass

21 Using % to find Average Atomic Mass Usually we only know the percents of various isotopes that make up different elements, we can use this to calculate the average atomic mass. If we have 100% chlorine: 75.77% of mass is 35 ->.7577x35 = % of mass is 37->.2423x37= 8.96 Add the 2 together to get the atomic mass: =

22 Practice Oxygen has 3 isotopes 16 O, 17 O, 18 O 99.76% of mass is 16 O 0.04% of mass is 17 O 0.20% of mass is 18 O What is the average atomic mass? Find the atomic mass if 99.64% of mass is 14 N and 0.36% is 15 N. 3-22

23 A Simple Version of the Periodic Table 3-23

24 Periodic Table When looking at periodic table elements are arranged in horizontal rows by increasing atomic number. Horizontal rows are called Periods Periods go left to right 3-24

25 Periodic Table The vertical columns are called Groups or Families Elements in families share similar properties 3-25

26 Metals, Semimetals, Non-Metals All elements on the periodic table are grouped as metals, semimetals or metalloids, or non-metals. Due to the arrangement of the periodic table, it is easy to identify each type of element. 3-26

27 Figure 3.12: Elements classified as metals and nonmetals. 3-27

28 Metals: Fall to left and under the stairs Properties of Metals: Efficient conduction of heat and electricity Malleability Ductility A lustrous appearance Positively charged ions 3-28

35 Group 8A or 18: Noble Gases Do not react easily with anything, due stable electron configuration All other elements strive to reach noble gas configuration for maximum stability by reacting with other elements. 3-35

36 Transition Metals: Group 3B-12B 3-36

37 Who is a solid, liquid or gas? When we look at the elements on the periodic table, who is a solid, liquid or gas in their natural state? Most elements are not found in their elemental state, most elements are found in compounds with other elements. Most elements on the periodic table are solids, so we will point out those who are gas or liquid. 3-37

38 Liquids Only 2 elements in their elemental form are a liquid at 25 degrees Celsius: Mercury and Bromine 3-38

39 Gases More elements exist in their elemental form as a gas, but there are some important distinctions to make about these gases. The noble gases are a gas, called monatomic gas. This means that the prefix mono- means one. And monatomic gases exist as individual atoms. Figure 3.13: A collection of argon atoms. 3-39

41 Diatomic molecules There are 7 elements that exist as diatomic molecules, you will simply need to find a way to memorize these. If you notice, all of the halogens fall in this category, and then hydrogen, nitrogen, and oxygen. 3-41

42 What is an ion? When we discussed atoms before, we were always looking at a neutral atom. Neutral atoms always have equal numbers of protons and electrons. protons = +1 charge electrons = -1 charge When atoms have unequal numbers of protons and electrons, then the atom is a charged particle called an ion. 3-42

43 Ion Facts Ions are atoms, or groups of atoms, with a charge. The charge is created by different numbers of protons and electrons. In an atom ONLY electrons can move. Atoms gain or lose electrons to become ions. 3-43

44 Cations and Anions There are 2 types of ions: cations and anions. Cations are ions with a (+) positive charge. To form a cation, an atom has lost electrons. Example: Na loses an electron and becomes Na + Anions are ions with a negative charge. To form an anion, an atom has gained electrons. Example: Cl gains an electron and becomes Cl

45 Basic Names for Ions Cations do not change names from their neutral atoms. Example: Magnesium loses 2 electrons and becomes Mg 2+ which is named magnesium ion. Anions change the end of their name to ide. Example: Chlorine gains an electron and becomes Cl -. We would change the name from chlorine to chloride. 3-45

47 How to Determine the Charge When determining the charge for an atom we can use the periodic table to help. The number of valence electrons determines the charge. All atoms want 8 valence electrons. If an atom has 1-3 valence electrons the atom will lose them to become positive. If an atom has 6-8 valence electrons the atom will gain electrons to become negative. We can determine the charge by looking at the periodic table. 3-47

48 Figure 3.19: The ions formed by selected members of groups 1, 2, 3, 6, and

49 Practice Determine the name and charge of the following ions: Potassium Bromine Calcium Sulfur Aluminum Strontium Cesium 3-49

50 Ions and Compounds Any time a bond is formed between 2 or more ions, we call this an ionic compound. In an ionic compound the overall charge must be zero. This means there must be cations and anions present. Example: Na + + Cl - -> NaCl Each atom has a charge of +1 or -1, when we add this together it comes out to be zero. 3-50

51 If we add two ions together and they are not equal, then we must add another ion to balance the charge. Example: Mg Cl - -> MgCl

52 IONS Cations lose e- and become positively charged. They keep their name. Anions gain e- and become negatively charged. Change the ending to ide. When combined to form a compound, cationscome first then anion. Net charge on the compound is 0. Ex. Magnesium oxide. What are the ions and what does the compound look like? 3-52

Material: laboratory display of the elements and a wall periodic table is required. Objective: To learn the use of periodic table for writing electron configuration of elements. INTRODUCTION Basic building

ATOMIC STRUCTURE AND THE PERIODIC TABLE CHAPTER 4 WORKSHEET PART A Given the following isotopes, determine the atomic number, the mass number, the number of protons, electrons and neutrons. Isotope Symbol

Unit 3 Review Chapters 4 (Atomic Structure) & 6 (Periodic Table) Part 1: Answer the following questions. 1. a. Which scientist created the first modern atomic theory? John Dalton b. What was his theory?

Chapter 5 TEST: The Periodic Table name HPS # date: Multiple Choice Identify the choice that best completes the statement or answers the question. 1. The order of elements in the periodic table is based

Chapter 3 Atoms and Elements 1 Elements Elements are pure substances that cannot be separated into simpler substances by ordinary laboratory processes the building blocks of matter listed on the inside

UNIT (2) ATOMS AND ELEMENTS 2.1 Elements An element is a fundamental substance that cannot be broken down by chemical means into simpler substances. Each element is represented by an abbreviation called

PERIODIC TABLE OF ELEMENTS, a Russian scientist is credited with creating the periodic table. Periods tell us how many are in the atoms of each element. Groups help us to know how many electrons are in

Date: Science 10 4.1 Atomic Theory & Bonding What is an Atom? smallest particle of an element that still has the properties of that element An atom = proton(s) + electron(s) + neutron(s) (PEN) Fun Fact:

EXPERIMENT 4 The Periodic Table - Atoms and Elements INTRODUCTION Primary substances, called elements, build all the materials around you. There are more than 109 different elements known today. The elements

Name: Date: 1. Which of the following best describes an atom? A. protons and electrons grouped together in a random pattern B. protons and electrons grouped together in an alternating pattern C. a core

1. Which characteristics describe most nonmetals in the solid phase? (1) They are malleable and have metallic luster. (2) They are malleable and lack metallic luster. (3) They are brittle and have metallic

1. The elements on the Periodic Table are arranged in order of increasing A) atomic mass B) atomic number C) molar mass D) oxidation number 2. Which list of elements consists of a metal, a metalloid, and

6 THE PERIODIC TABLE SECTION 6.1 ORGANIZING THE ELEMENTS (pages 155 160) This section describes the development of the periodic table and explains the periodic law. It also describes the classification

Periodic Table Questions 1. The elements characterized as nonmetals are located in the periodic table at the (1) far left; (2) bottom; (3) center; (4) top right. 2. An element that is a liquid at STP is

ATOMIC THEORY The smallest component of an element that uniquely defines the identity of that element is called an atom. Individual atoms are extremely small. It would take about fifty million atoms in

The following are topics and sample questions for the first exam. Topics 1. Mendeleev and the first periodic Table 2. Information in the Periodic Table a. Groups (families) i. Alkali (group 1) ii. Alkaline

Atomic Structure Investigation 14A 14A Atomic Structure What is inside an atom? We once believed that atoms were the smallest units of matter. Then it was discovered that there are even smaller particles

Review- The Periodic Table Name Date Block Matching: Match the description in with the correct term in. Write the letter in the blank provided. Each term matches with only one description, so be sure to

Dalton s s Atomic Theory 1. Elements are made of tiny particles called atoms. 2. All atoms of a given element are identical (not exactly; isotopes) 3. The atoms of a given element are different from those

1 The Periodic Table Scientists had identified certain substances as elements and so there were many attempts to arrange the known elements so that there were some correlations between their known properties.

Name Class Date The Periodic Table ELECTRONS AND THE STRUCTURE OF ATOMS 6.1 Organizing the Elements Essential Understanding Although Dmitri Mendeleev is often credited as the father of the periodic table,

CHEM100 Week 4 Notes Page 1 of 6 Scientists create models to understand how things work, including atoms. Dalton created a theory for the atom with these 5 postulates 1. Elements consist of one or more

Chapter 2 Atoms, Molecules, and Ions 1. Methane and ethane are both made up of carbon and hydrogen. In methane, there are 12.0 g of carbon for every 4.00 g of hydrogen, a ration of 3:1 by mass. In ethane,

Chapter 5 Notes: Ions and Ionic Compounds Sec. 5.1 Simple Ions 1. Relate the electron configuration of an atom to its chemical reactivity. 2. Determine an atom s number of valence electrons, and use the

The Periodic Table Bromfield Honors Chemistry Write your answers in your notebook What is a trend? What are some patterns or trends you have observed? Periodic Law Historical development Chemical Periodicity

Chapter 2 1 Chapter 2 Atoms and the Periodic Table Solutions to In-Chapter Problems 2.1 Each element is identified by a one- or two-letter symbol. Use the periodic table to find the symbol for each element.

Chapter 6 The Periodic Table Organizing the Periodic Table In a grocery store, the products are grouped according to similar characteristics. With a logical classification system, finding and comparing

Chemistry 25 Chapter 4 Atoms and Elements Experiencing Atoms What is ATOM? Atoms are incredibly small, yet they compose everything. Atoms are the pieces of elements. Properties of the atoms determine the

Atomic Structure Atoms and elements Everything in the world is made up from about 100 elements. Every element is made up of very small particles called atoms. An element is a substance in which all the

Periodic Table Extra Practice 1. Which of the following elements in Period 3 has the greatest metallic character? 1) Ar 3) Mg 2) Si 4) S 2. Which sequence of atomic numbers represents elements which have

CHAPTER 1 The Nature of Chemistry Objectives You will be able to do the following. 1. Describe how science in general is done. 2. Given a description of a property of a substance, identify the property

Unit 2 Periodic Behavior and Ionic Bonding 6.1 Organizing the Elements I. The Periodic Law A. The physical and chemical properties of the elements are periodic functions of their atomic numbers B. Elements

Name: Class: Date:, ID: A The Periodic Table Multiple Choice Identify the choice that best completes the statement or answers the question: 1. What are the elements with atomic numbers from 58 to 71 called?

Periodicity and the Periodic Table the result Dmitri Mendeleev arranged elements in order of their atomic numbers, such that elements with similar properties fell into the same column or group. The Periodic

CHAPTER 12 1 Arranging the Elements SECTION The Periodic Table BEFORE YOU READ After you read this section, you should be able to answer these questions: How are elements arranged on the periodic table?

Introduction to Chemistry Chapter 5 1 Atoms, Molecules, Formulas, and Subatomic Particles The Atom: The smallest particle of an element that can exist and still have the properties of the element building

Chemistry: The Periodic Table and Periodicity Name: Hour: Date: Directions: Answer each of the following questions. You need not use complete sentences. 1. Who first published the classification of the

1. The atomic number of an atom is always equal to the total number of A. neutrons in the nucleus B. protons in the nucleus 2. All of the atoms of argon have the same A. mass number B. atomic number C.

Trends of the Periodic Table Diary Trends are patterns of behaviors that atoms on the periodic table of elements follow. Trends hold true most of the time, but there are exceptions, or blips, where the

Chemistry: The Periodic Table and Periodicity Name: per: Date:. 1. By what property did Mendeleev arrange the elements? 2. By what property did Moseley suggest that the periodic table be arranged? 3. What

Unit 1 The Periodic Table: Periodic trends There are over one hundred different chemical elements. Some of these elements are familiar to you such as hydrogen, oxygen, nitrogen and carbon. Each one has

Composition and Structure of the Atom Atom: basic unit of an element; smallest unit that retains chemical properties of an element Subatomic particles: Small particles that are the building blocks from

SACE Stage 1 Chemistry - The Essentials 1. Structure and Properties of the Atom 1.1 Atoms: A simple definition of the atom is that it is the smallest particle that contains the properties of that element.

7.4 Using the Bohr Theory LEARNING TIP Models such as Figures 1 to 4, on pages 218 and 219, help you visualize scientific explanations. As you examine Figures 1 to 4, look back and forth between the diagrams

Lesson Outline for Teaching Lesson 1: Using the Periodic Table A. What is the periodic table? 1. The periodic table is a chart of the elements arranged into rows and columns according to their chemical

Unit 3.2: The Periodic Table and Periodic Trends Notes The Organization of the Periodic Table Dmitri Mendeleev was the first to organize the elements by their periodic properties. In 1871 he arranged the

CHAPTER 1 2 Ionic Bonds SECTION Chemical Bonding BEFORE YOU READ After you read this section, you should be able to answer these questions: What is ionic bonding? What happens to atoms that gain or lose

CHAPTER 1 1 Electrons and Chemical Bonding SECTION Chemical Bonding BEFORE YOU READ After you read this section, you should be able to answer these questions: What is chemical bonding? What are valence

Isotopes Isotopes are atoms of the same element that have different masses due to different numbers of neutrons. See the example below for two isotopes of oxygen. One has 8 neutrons while the other has

CHEMISTRY TEST: THE PERIODIC TABLE Directions: Multiple Choice For each of the following questions, choose the answer that best answers the question and place it on your answer sheet. 1. Which of the following

Reading Guide - Chapter 8.1 Periodic Properties of the Elements Section 1 - Main Group Elements Patterns of Behavior of Main Group Elements (Groups 1, 2, and 13-18) 1. Elements in the same group have the

Basic Chemistry Why do we study chemistry in a biology course? All living organisms are composed of chemicals. To understand life, we must understand the structure, function, and properties of the chemicals

Name Date STUDY GUIDE CHAPTER 1 ATOMS AND ELEMENTS 1) DESCRIBE THE RUTHERFORD-BOHR ATOMIC MODEL All matter is made of small particles called atoms. An atom is the smallest unit of matter that retains the

Chapter 6. Periodic Relationships Among the Elements Student: 1. The nineteenth century chemists arranged elements in the periodic table according to increasing A. atomic number. B. number of electrons.

The Periodic Table Organizing the Elements A few elements, such as gold and copper, have been known for thousands of years - since ancient times Yet, only about 13 had been identified by the year 1700.

Question 1: Did Dobereiner s triads also exist in the columns of Newlands Octaves? Compare and find out. Only one triad of Dobereiner s triads exists in the columns of Newlands octaves. The triad formed

Chapter 4 Page 1 Chapter 4: Atoms and Elements Atoms are EXTREMELY SMALL particles out of which all knownmatter is made. They are the smallest particle of a chemical element that still have the properties

Name: Date: 1. In the modern Periodic Table, the elements are arranged in order of increasing A. atomic number B. mass number C. oxidation number D. valence number 6. As the elements in Group IA are considered